Interferometry can resolve distance measurement to the nearest fringe or half-wave length of the light being used, and with some arrangements, each fringe distance can be subdivided into quarters and possibly eighths. However, such resolution has involved comparators that are troublesome to keep in balance.
I have discovered a way of producing a much finer resolution for an interferometer distance measurement. My finer resolution system is also fast, accurate, and simple to maintain, compared to previous coarse systems.